arrow-parens: false positive for generic arrow function #14

JamesHenry · 2019-01-15T13:45:39Z

This issue was initially reported here: eslint/typescript-eslint-parser#475

What version of TypeScript are you using?
2.8.3

What version of typescript-eslint-parser are you using?
15.0.0

What code were you trying to parse?

// Unexpected error: arrow-parens
const bar = <T>(t: T) => {};
// No error as expected
const bar2 = function <T>(t: T) {};

The text was updated successfully, but these errors were encountered:

jhoch · 2019-02-28T00:01:53Z

@JamesHenry @armano2 I'm still seeing this on version 1.4.2. I have a file in my repo called components/util/test.ts:

const foo = <T>(bar: any): void => {
  // Do nothing
}

which produces the following when I run eslint:

jasonhoch@hoch1:~/code/newfront-app
15:34:48$ yarn eslint components/util/test.ts
yarn run v1.13.0
$ /Users/jasonhoch/code/newfront-app/node_modules/.bin/eslint components/util/test.ts

/Users/jasonhoch/code/newfront-app/components/util/test.ts
  1:7   warning  'foo' is assigned a value but never used                                             @typescript-eslint/no-unused-vars
  1:13  error    Expected parentheses around arrow function argument having a body with curly braces  arrow-parens
  1:17  warning  'bar' is defined but never used                                                      @typescript-eslint/no-unused-vars
  1:22  warning  Unexpected any. Specify a different type                                             @typescript-eslint/no-explicit-any
  3:2   error    Missing semicolon                                                                    semi

✖ 5 problems (2 errors, 3 warnings)
  2 errors and 0 warnings potentially fixable with the `--fix` option.

error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

(See the error at 1:13). Here is my .eslintrc.js file:

module.exports = {
    'extends': [
      'airbnb',
      'plugin:@typescript-eslint/recommended',
    ],
    'env': {
      'jest': true,
    },
    'overrides': [{
      'files': ['*.ts', '*.tsx'],
      'rules': {
        'indent': 'off', // Conflicts
        'semi': ['error', 'always'], // Conflicts
      },
    }],
    'parser': '@typescript-eslint/parser',
    'parserOptions': {
      'project': './tsconfig.json',
    },
    'plugins': [
      '@typescript-eslint',
      'import',
    ],
    'rules': {
      'arrow-body-style': ['off'],
      'jsx-a11y/anchor-is-valid': ['error', {
        'components': ['Link'],
        'aspects': ['invalidHref', 'preferButton'],
      }],
      'jsx-quotes': ['warn', 'prefer-single'],
      'react/jsx-filename-extension': ['warn', { 'extensions': ['.js', '.jsx', '.tsx'] }],
      'react/jsx-closing-tag-location': ['off'],
      'react/jsx-curly-brace-presence': ['error', { 'props': 'never', 'children': 'ignore' } ],
      'react/jsx-one-expression-per-line': ['off'],
      'react/prop-types': ['off'],
      'semi': ['warn', 'never'],
      '@typescript-eslint/explicit-function-return-type': ['warn', { 'allowExpressions': true }],
      '@typescript-eslint/indent': ['error', 2],
    },
    'settings': {
      'import/resolver': {
        'typescript': {},
      },
    },
}

and the lines in my package.json:

"devDependencies": {
    ...
    "@typescript-eslint/eslint-plugin": "^1.4.2",
    "@typescript-eslint/parser": "^1.4.2",
    ...
}

We've had a smooth experience moving over from TSLint, with this one glitch. Looking at #176, it looks like you guys test for this case. Any idea what the problem could be? Let me know if I can help!

Also fix up the regex for vscode launching eslint-plugin tests so it matches all tests Closes #14

jinasonlin · 2019-05-10T02:36:45Z

I still get false positive.

`@typescript-eslint/parser` version

1.7.1-alpha-28

rule

"arrow-parens" : ["as-needed", { "requireForBlockBody": true }]

// Expected parentheses around arrow function argument having a body with curly braces.eslint(arrow-parens)
const foo = <T>(t: T): void => { console.info(t); }

// the following is correct
const foo = (t) => { console.info(t); }

bradzacher · 2019-05-10T03:46:10Z

You have the missing piece of the puzzle!
The config that causes it to fail!

tinymins · 2019-05-30T07:13:56Z

I've the same problem, when will this problem get fixed and published?

tinymins · 2019-05-30T07:30:11Z

"@typescript-eslint/eslint-plugin": "^1.9.0",
"@typescript-eslint/parser": "^1.9.0",
"eslint": "^5.16.0",
"eslint-config-airbnb-base": "^13.1.0",
"eslint-friendly-formatter": "^4.0.1",
"eslint-import-resolver-webpack": "^0.11.1",
"eslint-loader": "^2.1.2",
"eslint-plugin-import": "^2.17.3",
"eslint-plugin-vue": "^5.2.2",

oli-laban · 2019-06-10T21:35:52Z

I'm also experiencing this with default airbnb arrow-parens config:

'arrow-parens': ['error', 'as-needed', {
  requireForBlockBody: true,
}],

// Expected parentheses around arrow function argument having a body with curly braces.
export const makeRequest = async <T>(
  method: RequestMethod,
  urlPath: string,
  body: {} = {},
  extraHeaders: RequestHeaders = {},
  throwGeneralError: boolean = true,
  suppressErrors: boolean = false,
): Promise<T | null> => {
  ...
};

"eslint": "^5.15.0",
"eslint-config-airbnb": "^17.1.0",
"eslint-import-resolver-alias": "^1.1.2",
"eslint-plugin-import": "^2.16.0",
"eslint-plugin-jsx-a11y": "^6.2.1",
"eslint-plugin-react": "^7.12.4",
"@typescript-eslint/eslint-plugin": "^1.9.0",
"@typescript-eslint/parser": "^1.9.0",

- disable eslint rule as typescript linter is false-positive: typescript-eslint/typescript-eslint#14 - move some logic back to store

aldarund · 2020-05-15T23:01:26Z

Still issue. It happens when { "requireForBlockBody": true } otherwise it don't happen.
Maybe it will be fixed one day :) Issue number 14. Is it oldest one not fixed i wonder
happens on latest eslint 7 and the fix action totally break code

mdjermanovic · 2020-07-03T20:54:04Z

This is fixed in eslint v7.4.0

JamesHenry mentioned this issue Jan 15, 2019

arrow-parens: false positive for generic arrow function eslint/typescript-eslint-parser#475

Closed

JamesHenry pushed a commit that referenced this issue Jan 17, 2019

Fix: incorrect type-annoation-spacing test (#14)

6e31f4f

JamesHenry pushed a commit that referenced this issue Jan 17, 2019

Fix: incorrect type-annoation-spacing test (#14)

d20ec1c

JamesHenry pushed a commit that referenced this issue Jan 18, 2019

Fix: incorrect type-annoation-spacing test (#14)

1cf39d8

JamesHenry added the package: parser Issues related to @typescript-eslint/parser label Jan 18, 2019

bradzacher added bug Something isn't working package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin migration-test and removed package: parser Issues related to @typescript-eslint/parser labels Jan 18, 2019

armano2 mentioned this issue Feb 1, 2019

test(eslint-plugin): add test case for eslint arrow-parens #176

Merged

armano2 closed this as completed in #176 Feb 1, 2019

armano2 reopened this Feb 28, 2019

bradzacher added a commit that referenced this issue Apr 15, 2019

test(eslint-plugin): arrow-paren: add extra case

18d4095

Also fix up the regex for vscode launching eslint-plugin tests so it matches all tests Closes #14

bradzacher mentioned this issue Apr 15, 2019

test(eslint-plugin): arrow-paren: add extra case #432

Merged

JamesHenry closed this as completed in #432 Apr 24, 2019

bradzacher reopened this May 10, 2019

bradzacher added the enhancement: new base rule extension New base rule extension required to handle a TS specific case label May 10, 2019

bradzacher removed the bug Something isn't working label Jun 10, 2019

boonyasukd added a commit to boonyasukd/vue3-rfc-ts-simple that referenced this issue Jul 14, 2019

misc. improvements

915e020

- disable eslint rule as typescript linter is false-positive: typescript-eslint/typescript-eslint#14 - move some logic back to store

lyleunderwood mentioned this issue Jul 18, 2019

Implement arrow-parens to support type parameters gajus/eslint-plugin-flowtype#417

Merged

bradzacher added the good first issue Good for newcomers label Jul 27, 2019

bradzacher closed this as completed Jul 3, 2020

github-actions bot locked as resolved and limited conversation to collaborators Aug 3, 2020

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arrow-parens: false positive for generic arrow function #14

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arrow-parens: false positive for generic arrow function #14

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